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Summary of Significant Accounting Policies - Investments (Details) $ / shares in Units, $ in Thousands	3 Months Ended		12 Months Ended
	Jun. 30, 2017 USD ($)	Dec. 31, 2016 USD ($) $ / shares	Dec. 31, 2019 USD ($) shares	Dec. 31, 2018 USD ($) shares	Dec. 31, 2017 USD ($)	Jun. 30, 2019 shares
Investment in available for sale securities
Unrealized gains (losses) on equity securities, net			$ (41,898)	$ (20,724)	$ 0
Impairment of assets			115,201	66,346	$ 5,082
Class A common shares | RMR Inc.
Investment in available for sale securities
Investment in common shares (in shares) | shares						2,637,408
Five Star
Investment in available for sale securities
Impairment of assets		$ 2,795
Weighted average quoted market prices (in dollars per share) | $ / shares		$ 2.70
Five Star
Investment in available for sale securities
Fair value of investment			1,571	2,033
Unrealized gains (losses) on equity securities, net			$ (462)	$ (4,320)
Impairment of assets	$ 5,082
Five Star | Common Shares
Investment in available for sale securities
Investment in common shares (in shares) | shares			423,500	423,500
Reverse stock split ratio			0.1	0.1
Cost basis for shares owned			$ 6,353

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